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tarfile data/tar filter bypass via hard link to a symlink #157190

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tarfile data/tar filter bypass via hard link to a symlink#157190
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StanFromIreland
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3.10 (EOL)end of life3.11only security fixes3.12only security fixes3.13only security fixesstdlibStandard Library Python modules in the Lib/ directorytype-securityA security issue

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@StanFromIreland
StanFromIreland
opened on Sep 8, 2026

On CPython 3.13.15 for Linux, an attacker-controlled tar archive extracted with the tar or data filter can make tarfile change the permissions and modification time of an existing file outside the extraction directory. The archive also leaves a path inside the extracted tree that resolves to the outside file. Opening that path returns the outside file's content.

This was incidentally fixed by 5a57248 for 3.14+ which changed os.link to use AT_SYMLINK_FOLLOW.

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Activity

  1. StanFromIreland
    self-assigned this
    on Sep 8, 2026
  2. StanFromIreland
    added this to Tarfile issues 🗄️on Sep 8, 2026
  3. StanFromIreland
    added
    type-securityA security issue
    stdlibStandard Library Python modules in the Lib/ directory
    3.11only security fixes
    3.10 (EOL)end of life
    3.12only security fixes
    3.13only security fixes
    on Sep 8, 2026
  4. encukou
    added 2 commits that reference this issue on Sep 10, 2026

    gh-157190: Follow symlinks when extracting `tarfile` hard links (GH-1…

    b38be2e

    [3.13] gh-157190: Fix tarfile `data`/`tar` filter bypass via hard lin…

    b8f23e3
  5. clin1234
    added a commit that references this issue on Sep 12, 2026

    pythongh-157190: Follow symlinks when extracting `tarfile` hard links (…

    540c098
  6. johnslavik
    added a commit that references this issue on Sep 14, 2026

    pythongh-157190: Follow symlinks when extracting `tarfile` hard links (…

    74b1827
  7. cesararroba
    added a commit that references this issue on Sep 21, 2026

    chore(security): accept CVE-2026-82049 in Grype and bump anyio in the…

    24f936e
  8. freakboy3742
    added a commit that references this issue on Sep 29, 2026

    [3.11] pythongh-157190: Fix tarfile `data`/`tar` filter bypass via ha…

    5283481
  9. pablogsal
    added 2 commits that reference this issue on Sep 29, 2026

    [3.10] gh-157190: Fix tarfile `data`/`tar` filter bypass via hard lin…

    197663d

    [3.11] gh-157190: Fix tarfile `data`/`tar` filter bypass via hard lin…

    28f3154
  10. StanFromIreland
    added a commit that references this issue on Sep 30, 2026

    [3.14] gh-157190: Follow symlinks when extracting `tarfile` hard links (

    c66df4e
  11. Yhg1s
    added a commit that references this issue on Sep 30, 2026

    [3.12] gh-157190: Fix tarfile `data`/`tar` filter bypass via hard lin…

    cc16898
  12. serhiy-storchaka
    added a commit that references this issue on Oct 10, 2026

    [3.15] gh-157190: Follow symlinks when extracting `tarfile` hard links (

    cccc7ec
  13. StanFromIreland
    closed this as completedon Oct 11, 2026
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3.10 (EOL)end of life3.11only security fixes3.12only security fixes3.13only security fixesstdlibStandard Library Python modules in the Lib/ directorytype-securityA security issue

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